Frank Swarbrick wrote:
[snip]
On Fri, 15 May 2009 09:27:42 -0400, Thompson, Steve
<steve_thomp...@stercomm.com> wrote:
I have been a bit of experimenting with z/OS QSAM files from a Cobol
program
and I find that the manuals don't exactly agree with my results. The
manuals seem to imply that if you use the BLOCK CONTAINS clause (whether
0 or something else) then the file has a RECFM of either VB or FB. And
if you don't include it then it's either V or B.
We are not using a vendor. We have systems and applications programmers
that come from the MVS world, so we're going with that expertise. Though I
suppose the fact that I am asking these questions here might indicate that
said expertise is perhaps not sufficient? Hmmm...
[snip]
Both VSE and z/OS require the AS- prefix in order for Cobol to distinguish
between between a VSAM ESDS and a regular SAM file. Other than that, yes,
only the last "node" has any meaning. Nonetheless our conversion program is
going to remove all of the superfluous stuff. I have been trying to get my
fellow programmers to cut out this information for years, but with little
success. Hopefully this way people will have fewer bad examples to follow!
Frank,
I've been watching this thread evolve and I'd like to throw
in some thoughts here.
There was some change in behavior in COBOL + QSAM a few years
ago, and the documentation never did, to my perception, do a
good job of pointing this out.
Here is an extract from one page in our course "Enterprise COBOL
Update I: Essentials":
While not strictly a change to the language, there has
been a change to the way OPEN works that is worthwhile
knowing about
* Historically, coding BLOCK CONTAINS ensured the value
in your program would be used for block size
* If you wanted to obtain the existing block size (for
input files) or to set the blocksize in JCL (for
output files) you coded BLOCK CONTAINS 0 RECORDS in your FD
The new behavior is this:
* Block size in the label overrides BLOCK CONTAINS value
in the program
* The implications are:
+ For input files, may now simply omit the BLOCK CONTAINS
clause: it will be ignored / overridden
+ For output files, BLOCK CONTAINS 0 is required if DSORG,
LRECL, and RECFM are not specified on the DD statement
+ BLOCK CONTAINS 0 is not necessary if you code DSORG,
LRECL, and RECFM on the DD statement (the system will
choose blocksize for you)
--------------
[of course, if you pre-allocate the file using ISPF 3.2 or
some other mechanism, existing label information will be
used there, too.]
--------------
Regarding your systems and applications programmers with
MVS experience: COBOL has gone through extensive changes
of late, and the experience of these people may be somewhat
out of date.
I really recommend the course mentioned above. It's only
two days but it catches experienced programmers up to
speed in terms of new features and approaches.
The details are here:
http://www.trainersfriend.com/COBOL_Courses/d704descr.htm
As with all our course descriptions, this page has further
links to more detail, especially note the links to the
pages with more detailed course objectives and the very
detailed topical outline.
-------------
Kind regards,
-Steve Comstock
The Trainer's Friend, Inc.
303-393-8716
http://www.trainersfriend.com
z/OS Application development made easier
* Our classes include
+ How things work
+ Programming examples with realistic applications
+ Starter / skeleton code
+ Complete working programs
+ Useful utilities and subroutines
+ Tips and techniques
==> Check out the Trainer's Friend Store to purchase z/OS <==
==> application developer toolkits. Sample code in four <==
==> programming languages, JCL to Assemble or compile, <==
==> bind and test. <==
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